AT&T is the last of the four major U.S. carriers to announce its pricing plans for the Samsung Galaxy Tab. AT&T just confirmed that it will sell the Galaxy Tab unsubsidized for $649.99 and will offer it with pre-paid data plans. Customers can get pay-as-you-go pricing at $14.99 for 30 days or up to 250 MB data transfer, whichever comes first. The larger option of $25 will get users 30 days of up to 2 GB of data.

Those options can also be used for auto-renewals with a credit or debit cards, so users can in effect sign-up for “contracts” that can be broken at any time without penalty.

The Galaxy Tab will go on sale November 21st, offering customers the first Android 2.2 tablet sanctioned with the Android Market, Google Mobile Services, Adobe Flash Player 10.1, and a 1 GHz Hummingbird processor. Customers who purchase a Tab will also receive a $50 credit to the Samsung Media Hub for renting movies. Sprint has offered a similar deal to people who purchase the Samsung Epic 4G.

AT&T’s decision to offer the Galaxy Tab without a subsidy and for a higher off-contract price than all of its competitors is surprising. Conspiracy theorists are sure to claim this as proof of an Apple bias at AT&T, but I’m speaking more to the disadvantage of owning a Tab on AT&T as opposed to the other networks. Verizon offers an arguably better network and more data, Sprint offers a cheaper price and more data, and T-Mobile offers more data and a cheaper price. Apple has the benefit of offering PAYG pricing, but its questionable how appealing that will be for a device of this nature. We’ll find out on the 21st when the Galaxy Tab goes on sale.